Twin polymerization is a polymerization process which creates two different polymer structures from one monomer. The concept of twin polymerization has been investigated by Spange et al. (see for example, Advanced Materials 2009, 21, 2111-2116; Angewandte Chemie International Edition 2007, 46, 628-632; Angewandte Chemie International Edition 2009, 48, 8878-8881). Examples for monomers undergoing twin polymerization are silyl ethers of furfuryl alcohol and 2-hydroxymethyl phenol:

The scission of the silyl ether bonds of the sketched monomers and further polymerization and/or polycondensation reactions lead to an interpenetrating network of silicon dioxide and an organic polymer. In the first case, a furfuryl alcohol resin will be formed from the organic moieties of the component as the polymerization of furfuryl alcohol usually leads to crosslinking by side reactions. In case of the second monomer, a phenol-formaldehyde resin can be formed from the organic part of the molecule.
The twin polymerization reaction of tetrafurfuryloxy silane is shown as follows:
